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 With your pair define the following words:  Elements, compounds, mixtures and molecules  Leave 3 lines below each definition  Gallery walk: you have.

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Presentation on theme: " With your pair define the following words:  Elements, compounds, mixtures and molecules  Leave 3 lines below each definition  Gallery walk: you have."— Presentation transcript:

1  With your pair define the following words:  Elements, compounds, mixtures and molecules  Leave 3 lines below each definition  Gallery walk: you have 5 minutes to see what your classmates have written and add anything you like onto your definitions

2  At the center of each atom is the nucleus. The nucleus is a cluster of particles called protons and neutrons. Protons have a plus (+) charge, and neutrons are neutral (that is, they don't have a charge).  Most of the atom is empty space! Electrons have a minus (-) charge, and so there are enough electrons to balance out the (+) protons.  Electrons are so light that they really don't count towards the total weight of the atom.

3  Electrons in the atoms, cannot move anyway they wish. They are restricted to levels (n).  The first level can hold only two electrons. (ex: H)  The second and third level can hold eight electrons (ex: C)  Hydrogen  Carbon 1n 1p

4 16n 16p 17n 17p

5 5p 5n

6  The columns in the Period Table indicate the amount of Valence electrons. Those are the ones found in the outermost level.  These electrons have a very special job... They form bonds!!!!

7 http://www.webelements.com/

8 1. Search for the elements (Sodium, Calcium, Aluminium, Carbon, Phosphorus, Oxygen, Fluorine and Neon) in the periodic table 2. Create a table to include the following information: 1.Element 2.Symbol 3.Amount of protons, neutrons and electrons 4.Draw the atomic structure for each of these atoms 5.Determine the amount of Valence electrons in each of them

9  Ionic bonds  Ionic bonds happen when one atom gives at least one electron to another atom.  The atom that gets an extra electron ends up with a (-) charge and is called an anion. The atom that gives away an electron ends up with a (+) charge and is called a cation.  Now, those (+) and (-) charges have a strong attraction to each other - they sit next to each other and refuse to move.  Covalent bonds  Covalent bonds happen when two atoms share electrons - kind of like 2 atoms holding hands.  Sometimes molecules share more than one pair of electrons. If two pairs of electrons are shared then a double bond is formed, and if three pairs are shared then a triple bond is formed. It is not possible to form a "quadruple" bond!

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11  Ionic bonds  Covalent bonds

12  NaF  KCl  CaO  CaS  MgCl 2  HCl  O 2  H 2 O  CO 2  NH 3  CH 4

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